High-rate cmp polishing method

ABSTRACT

The invention provides a method for polishing or planarizing a wafer of at least one of semiconductor, optical and magnetic substrates. The method includes rotating a polishing pad having radial feeder grooves in the polishing layer separating the polishing layer into polishing regions. The radial feeder grooves include a series of biased grooves connecting a pair of adjacent radial feeder grooves. A majority of the biased grooves have either an inward bias toward the center or an outward bias toward the outer edge of the polishing pad. Pressing and rotating the wafer against the rotating polishing pad for multiple rotations of the polishing pad at a fixed distance from the center of the polishing pad increases polishing or planarizing removal rate of the wafer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of U.S. Ser. No. 15/624,964,filed Jun. 16, 2017, now pending, which was a continuation-in-partapplication of U.S. Ser. No. 15/623,195, filed Jun. 14, 2017, nowpending.

BACKGROUND

The present invention relates to grooves for chemical mechanicalpolishing pads. More particularly, the present invention relates togroove designs for increasing removal rate, improving global uniformityand reducing defects during chemical mechanical polishing.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting and dielectric materialsare deposited onto and removed from a surface of a semiconductor wafer.Thin layers of conducting, semiconducting and dielectric materials maybe deposited using a number of deposition techniques. Common depositiontechniques in modern wafer processing include physical vapor deposition(PVD), also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD) and electrochemicalplating, among others. Common removal techniques include wet and dryisotropic and anisotropic etching, among others.

As layers of materials are sequentially deposited and removed, theuppermost surface of the wafer becomes non-planar. Because subsequentsemiconductor processing (e.g., metallization) requires the wafer tohave a flat surface, the wafer needs to be planarized. Planarization isuseful for removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches and contaminated layers or materials.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize or polish work piecessuch as semiconductor wafers. In conventional CMP, a wafer carrier, orpolishing head, is mounted on a carrier assembly. The polishing headholds the wafer and positions the wafer in contact with a polishinglayer of a polishing pad that is mounted on a table or platen within aCMP apparatus. The carrier assembly provides a controllable pressurebetween the wafer and polishing pad. Simultaneously, a polishing medium(e.g., slurry) is dispensed onto the polishing pad and is drawn into thegap between the wafer and polishing layer. The polishing pad and wafertypically rotate relative to one another to polish a substrate. As thepolishing pad rotates beneath the wafer, the wafer sweeps out atypically annular polishing track, or polishing region, wherein thewafer's surface directly confronts the polishing layer. The wafersurface is polished and made planar by chemical and mechanical action ofthe polishing layer and polishing medium on the surface.

Reinhardt et al., U.S. Pat. No. 5,578,362 discloses the use of groovesto provide macrotexture to the pad. In particular, it discloses avariety of patterns, contours, grooves, spirals, radials, dots or othershapes. Specific examples included in Reinhardt are the concentriccircular and the concentric circular superimposed with an X-Y groove.Because the concentric circular groove pattern provides no direct flowpath to the edge of the pad, the concentric circular groove has proventhe most popular groove pattern.

Lin et al., in U.S. Pat. No. 6,120,366, at FIG. 2, disclose acombination of circular plus radial feeder grooves. This exampleillustrates adding twenty-four radial feeder grooves to a concentriccircular groove pattern. The disadvantage of this groove pattern is thatit provides limited improvement in polishing with a substantial increasein slurry usage and shorter pad life due to less landing area on thepolishing pad.

Notwithstanding, there is a continuing need for chemical mechanicalpolishing pads having better combination of polishing performance andslurry usage. Furthermore, there is a need for grooves that increaseremoval rate, lower slurry usage, improve global uniformity and reducedefects during chemical mechanical polishing.

STATEMENT OF INVENTION

An aspect of the invention provides a method for polishing orplanarizing a wafer of at least one of semiconductor, optical andmagnetic substrates, the method comprising the following: rotating apolishing pad, the polishing pad having a polishing layer having apolymeric matrix and a thickness, the polishing layer including acenter, an outer edge and a radius extending from the center to theouter edge of the polishing pad; radial feeder grooves in the polishinglayer separating the polishing layer into polishing regions, the radialfeeder grooves extending at least from a location adjacent the center toa location adjacent the outer edge; and each polishing region includinga series of biased grooves connecting a pair of adjacent radial feedergrooves, a majority of the biased grooves having either an inward biastoward the center or an outward bias toward the outer edge of thepolishing pad, both the inward and outward biased grooves movingpolishing fluid toward the outer edge of the polishing pad and eithertoward the wafer or away from the wafer depending upon inward bias oroutward bias and the direction of rotation of the polishing pad;distributing polishing fluid onto the rotating polishing pad and intothe radial feeder grooves and the series of biased grooves; and pressingand rotating the wafer against the rotating polishing pad for multiplerotations of the polishing pad at a fixed distance from the center ofthe polishing pad, the wafer being closer to the outer edge of thepolishing pad then the center of the polishing pad to increase removalrate of at least one component of the wafer.

An additional aspect of the invention provides a method for polishing orplanarizing a wafer of at least one of semiconductor, optical andmagnetic substrates, the method comprising the following: rotating apolishing pad, the polishing pad having a polishing layer having apolymeric matrix and a thickness, the polishing layer including acenter, an outer edge and a radius extending from the center to theouter edge of the polishing pad; radial feeder grooves in the polishinglayer separating the polishing layer into polishing regions, thepolishing regions being circular sectors defined by two adjacent radialfeeder grooves, a bisect line bisecting the polishing regions, theradial feeder grooves extending at least from a location adjacent thecenter to a location adjacent the outer edge; and each polishing regionincluding a series of biased grooves connecting a pair of adjacentradial feeder grooves, a majority of the biased grooves having either aninward bias toward the center of the polishing pad at an angle of 20° to85° from the bisect line or an outward bias toward the outer edge of thepolishing pad at an angle of 95° to 160° from the bisect line, both theinward and outward biased grooves moving polishing fluid toward theouter edge of the polishing pad and either toward the wafer or away fromthe wafer depending upon inward bias or outward bias and the directionof rotation of the polishing pad; distributing polishing fluid onto therotating polishing pad and into the radial feeder grooves and the seriesof biased grooves; and pressing and rotating the wafer against therotating polishing pad for multiple rotations of the polishing pad at afixed distance from the center of the polishing pad, the wafer beingcloser to the outer edge of the polishing pad then the center of thepolishing pad to increase removal rate of at least one component of thewafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top schematic view of an inward bias polishing pad havingeight polishing regions each having a series of inward biased groovesconnecting adjacent radial feeder grooves.

FIG. 1A is a partial break away schematic top view of the inward biaspolishing pad of FIG. 1.

FIG. 1B is a partial break away schematic top view of a series ofnon-isosceles trapezoid grooves of FIG. 1A rotated to render thetrapezoid legs parallel with the bottom of the drawing.

FIG. 1C is a partial break away schematic view of a radial feeder grooveof FIG. 1 with interconnected inward bias grooves.

FIG. 2 is a top schematic view of an outward bias polishing pad havingeight polishing regions each having a series of outward biased groovesconnecting adjacent radial feeder grooves.

FIG. 2A is a partial break away schematic top view of the outward biaspolishing pad of FIG. 2.

FIG. 2B is a partial break away schematic top view of a series ofnon-isosceles trapezoid grooves of FIG. 2A rotated to render thetrapezoid legs parallel with the bottom of the drawing.

FIG. 2C is a partial break away schematic view of a radial feeder grooveof FIG. 2 with interconnected outward bias grooves.

FIG. 3 is a schematic depiction of how inward bias grooves channelpolishing fluid toward the outer edge of the polishing pad to increasepolishing fluid residence time under a wafer for counterclockwise platenrotation.

FIG. 3A is a schematic depiction of how outward bias grooves channelpolishing fluid toward the outer edge of the polishing pad to decreasepolishing fluid residence time under a wafer for counterclockwise platenrotation.

FIG. 4 is a top schematic view of an inward bias polishing pad havingthree polishing regions each having a series of inward biased groovesconnecting adjacent radial feeder grooves.

FIG. 4A is a top schematic view of an outward bias polishing pad havingthree polishing regions each having a series of outward biased groovesconnecting adjacent radial feeder grooves.

FIG. 5 is a top schematic view of an inward bias polishing pad havingfour polishing regions each having a series of inward biased groovesconnecting adjacent radial feeder grooves.

FIG. 5A is a top schematic view of an outward bias polishing pad havingfour polishing regions each having a series of outward biased groovesconnecting adjacent radial feeder grooves.

FIG. 6 is a top schematic view of an inward bias polishing pad havingfive polishing regions each having a series of inward biased groovesconnecting adjacent radial feeder grooves.

FIG. 6A is a top schematic view of an outward bias polishing pad havingfive polishing regions each having a series of outward biased groovesconnecting adjacent radial feeder grooves.

FIG. 7 is a top schematic view of an inward bias polishing pad havingsix polishing regions each having a series of inward biased groovesconnecting adjacent radial feeder grooves.

FIG. 7A is a top schematic view of an outward bias polishing pad havingsix polishing regions each having a series of outward biased groovesconnecting adjacent radial feeder grooves.

FIG. 8 is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesof outward biased curved grooves connecting adjacent radial feedergrooves.

FIG. 8A is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesof inward biased curved grooves connecting adjacent radial feedergrooves.

FIG. 9 is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesof outward biased grooves connecting adjacent curved radial feedergrooves.

FIG. 10 is a top schematic view with one half broken away of an outwardbias polishing pad eight polishing regions each having a series ofoutward biased curved grooves connecting adjacent curved radial feedergrooves.

FIG. 11 is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesof outward biased curved grooves connecting adjacent stepped radialfeeder grooves.

FIG. 11A is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesof inward biased curved grooves connecting adjacent stepped radialfeeder grooves.

FIG. 11B is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesof inward biased curved grooves connecting adjacent stepped radialfeeder grooves.

FIG. 12 is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesof inward biased stepped grooves connecting adjacent radial feedergrooves.

FIG. 12A is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesof outward biased stepped grooves connecting adjacent radial feedergrooves.

FIG. 13 is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesof outward biased stepped grooves connecting adjacent stepped radialfeeder grooves.

FIG. 14 is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesincreased pitch inward bias stepped grooves between two series of normalpitched inward bias stepped grooves all connecting adjacent radialfeeder grooves.

FIG. 14A is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesincreased pitch outward bias curved grooves between two series of normalpitched outward bias curved grooves all connecting adjacent radialfeeder grooves.

FIG. 14B is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesincreased pitch inward bias curved grooves between two series of normalpitched inward bias curved grooves all connecting adjacent radial feedergrooves.

FIG. 14C is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesincreased pitch inward bias grooves between two series of normal pitchedinward bias grooves all connecting adjacent radial feeder grooves.

FIG. 15 is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesnormal pitch inward bias stepped grooves between two series of increasedpitch inward bias stepped grooves all connecting adjacent radial feedergrooves.

FIG. 15A is a top schematic view with one half broken away of an outwardbias polishing pad having eight polishing regions each having a seriesnormal pitch outward bias curved grooves between two series of increasedpitched outward bias curved grooves all connecting adjacent radialfeeder grooves.

FIG. 15B is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesnormal pitch inward bias curved grooves between two series of increasedpitch inward bias curved grooves all connecting adjacent radial feedergrooves.

FIG. 15C is a top schematic view with one half broken away of an inwardbias polishing pad having eight polishing regions each having a seriesnormal pitch inward bias grooves between two series of increased pitchinward bias grooves all connecting adjacent radial feeder grooves.

DETAILED DESCRIPTION

The groove pattern and method of the invention provide for controlledand uniform distribution of polishing fluids, such asabrasive-containing slurries and abrasive-free polishing solutions. Theefficient distribution allows the user to decrease slurry flow incomparison to conventional grooves. Furthermore the interconnectedgroove path allows polishing debris to leave the pad in an efficientmanner for lowering polishing defects. Finally, the groove patternimproves polishing uniformity, wafer profile, die scale uniformity andcan improve edge effects.

The term “trapezoid” as used herein and in the claims meansinterconnected grooves forming a quadrilateral or four-sided shapehaving only one pair of parallel sides. The trapezoid has two parallelbase sides and two legs connecting the base sides. All angles of thetrapezoid add up to 360°.

The term “non-isosceles trapezoid” as used herein and in the claimsmeans interconnected grooves forming a trapezoid having twonon-congruent legs or legs of a different length. The leg closer to thepad center has a length less than the leg closer to the perimeter.

The term “circular sector” as used herein and in the claims refers to aportion of a polishing pad defined by two radial feeder grooves and aperimeter arc that extends along the outer edge of the polishing pad.The radial feeder grooves can have a straight radial, curved radial,stepped radial or other shape.

The term “polishing fluid” as used herein and in the claims refers to anabrasive-containing polishing slurry or an abrasive-free polishingsolution.

The term “bias angle θ” as used herein refers to the angle between abisect line bisecting a polishing region and sloped bias groovesconnecting adjacent radial feeder grooves. The bisect line shifts withchanges in direction of the radial feeder grooves and represents theaverage from end-to-end of each bias groove.

The term “inward bias angle θ” as used herein and in the claims refersto a bias angle that slopes inward toward the center of the polishingpad measured left to right when viewed downward toward the top of thegrooves.

The term “outward bias angle θ” as used herein and in the claims refersto a bias angle that slopes outward toward the perimeter of thepolishing pad measured left to right when viewed downward toward the topof the grooves.

The term “wafer” encompasses magnetic, optical and semiconductorsubstrates. The conventions, such as wafer residence time, contained inthis specification assume a polishing fluid drop point to the left ofthe wafer for counter clockwise rotation and to right of the wafer forclockwise rotation as taken from a top view.

The term “poly(urethane)” as used herein and in the appended claims is apolymer formed by a reaction between isocyanates and compoundscontaining active-hydrogen groups, specifically including the following:(a) polyurethanes formed from the reaction of (i) isocyanates and (ii)polyols (including diols); and, (b) poly(urethane) formed from thereaction of (i) isocyanates with (ii) polyols (including diols) and(iii) water, amines or a combination of water and amines. Polishing padsof the invention are advantageously a polymer, but most advantageously apolyurethane polymer.

The groove pattern of the invention provides multiple benefits. Thefirst benefit is that a majority of the biased grooves sweep the waferin the same direction. Sweeping with all the biased grooves in the samedirection further increases the benefit. Sweeping a wafer in the samedirection pulses the wafer with grooves and provides a beneficialcumulative impact on polishing removal rate. Furthermore, because thebiased grooves align in the same direction, it is possible to polish thewafer without oscillating the carrier head or oscillate it with muchsmaller amplitude or slower oscillation rate. This allows the wafer tobe polished at a fixed location further away from the pad center, closerto the edge of the polishing pad. At these locations adjacent to theouter edge, the pad rotates faster than the center to further increaseremoval rate. In addition, polishing in a non-oscillation mode providesconsistent edge profiles over multiple wafers, and reduces defects,improves polishing pad life and retaining ring life due to less wearwith polishing pad and retaining ring. Turning off the oscillation alsoallows use of manufacturing tools with decreased platen size. This is ofparticular importance for dual platen and 450 mm size CMP tools. Inaddition, it is possible to use a combination of the number of radialgrooves, platen speed and bias angle θ to adjust center profile betweenfast and slow and to provide consistent flat profiles.

In addition, the feeder grooves and bias grooves combine to facilitateuniform slurry distribution across the polishing pad and provide betterslurry distribution across the wafer surface. This allows adjusting thepolishing rate profile across the wafer, improving global uniformity bychanging the platen speed or bias angle θ or both. Furthermore, thewafer edge profile can be adjusted as well by optimizing the bias angleθ or carrier speed or both. This is more critical for wafer-edge yieldin advanced logic and 3D NAND with extremely low edge exclusions.Typically, the polishing pad has at least three feeder grooves, and canbe varied between 3 to 32 grooves. Typically, the wafer alternatesbetween being over one radial feeder groove and multiple biased groovesand being over two or multiple radial feeder grooves and multiple biasedgrooves. This uniform distribution eliminates pooling at the carrierring and allows the polishing pad to operate in a more efficient manneror with decreased slurry flow.

Another unexpected feature of the invention is that it allows polishingat higher downforce than conventional grooves due to better slurrydistribution at wafer surface and reducing excessive heat and polishingtemperature between wafer and pad. This is particularly important forCMP metal polishing, such as copper, tantalum and tungsten polishing.These metal layers, dielectric layers, insulator layers and othermaterial layers all represent wafer components. The groove pattern ofthe invention operates with both porous and non-porous polishing pads.The groove pattern of the invention has particular utility for precisionpolishing with non-porous polishing pads, such as for atomic scalepolishing for removing a single monatomic layer at a time.

Since both inward and outward biased grooves direct polishing fluid offthe polishing pad, it provides efficient polishing debris removal forlower defects.

Referring to FIGS. 1 and 1A, the polishing pad 10 of the invention issuitable for polishing or planarizing at least one of semiconductor,optical and magnetic substrates. The polishing layer 12 has a polymericmatrix and a thickness 14. The polishing layer 12 includes a center 16,an outer edge 18 and a radius (r) extending from the center 16 to theouter edge 18. Advantageously the wafer remains positioned at a locationalong the radius r from the center 16 of the polishing pad 10 closer tothe outer edge 18 of the polishing pad then the center 16 of thepolishing pad 10 to increase removal rate of at least one component ofthe wafer. Radial feeder grooves 20, 22, 24, 26, 28, 30, 32 and 34initiate from center 16 or from optional circular groove 36. Radialfeeder grooves 20, 22, 24, 26, 28, 30, 32 and 34 separate the polishinglayer 12 into polishing regions 40, 42, 44, 46, 48, 50, 52 and 54. Inparticular, two adjacent radial feeder grooves, such as 20 and 22,combine with perimeter arc 19 of outer edge 18 to define polishingregion 40. Polishing region 40, along with polishing regions 42, 44, 46,48, 50, 52 and 54 have a shape of a circular sector with a smallcircular sector broken away at the center 16. The radial feeder grooves20, 22, 24, 26, 28, 30, 32 and 34 advantageously extend at least fromcircular groove 36 adjacent the center 16 to or adjacent the outer edge18.

Referring to FIGS. 1A and 1B, polishing region 40 includes a series ofstacked trapezoid groove regions 60, 62, 64, 66 and 68. Polishing region40 represents a circular sector of polishing pad 10 (FIG. 1) with thecenter region being groove-free. Parallel linear grooves or parallelbase grooves 160, 162, 164, 166, 168 and 170 define the top and bottomof the trapezoid groove regions 60, 62, 64, 66 and 68. Radial feedergroove segments 20 a, 20 b, 20 c, 20 d and 20 e of radial feeder groove20 define the left side of trapezoid groove regions 60, 62, 64, 66 and68, respectively. Radial feeder groove segments 22 a, 22 b, 22 c, 22 dand 22 e of radial feeder groove 22 define the right side of trapezoidgroove regions 60, 62, 64, 66 and 68, respectively. Polishing regions40, 42, 44, 46, 48, 50, 52 and 54 (FIG. 1) all include a series oftrapezoid groove regions spaced with parallel base grooves. Toaccommodate the shape of a circular polishing pad 10 or a circularsector shape of polishing regions 40, 42, 44, 46, 48, 50, 52 and 54,trapezoid groove regions are often cut to accommodate the outer edge 18or circular groove 36.

The trapezoid groove regions 60, 62, 64, 66 and 68 all representnon-isosceles trapezoid regions with the radial side segments being ofdifferent lengths. Because this grove pattern has an inward bias towardthe center, radial feeder groove segments 20 a, 20 b, 20 c, 20 d and 20e are longer than radial 22 a, 22 b, 22 c, 22 d and 22 e, respectively.In addition to each trapezoid groove region representing a non-isoscelestrapezoid, the perimeter of stacked trapezoid regions such as theperimeter of trapezoid regions 60 and 62 and the perimeter of trapezoidregions 60, 62 and 64 also define a non-isosceles trapezoid. Thetrapezoid region 70 adjacent the circular groove 36 has a portion brokenaway to accommodate the circular groove 36. Similarly, trapezoid grooveregions 80, 82, 84, 86, 88, 90, 92, 94, 96 and 98 adjacent outer edge 18all have portions broken away to accommodate the circular shape of theouter edge 18 of the polishing pad 10. Rotating the polishing pad sendsused polishing fluid through a portion of the series of biased groovesadjacent trapezoid groove regions 80, 82, 84, 86, 88, 90, 92, 94, 96 and98 over the outer edge 18 of the polishing pad 10 to allow flow of newpolishing fluid under the wafer.

Referring to FIG. 1A, the dashed line AA bisects polishing region 40 byconnecting center 16 to the midpoint of perimeter arc 19 of outer edge18. The base legs of spaced trapezoid groove regions 80, 82, 84, 86, 88,90, 92, 94 and 96 intersect line AA at an angle θ. For purposes of thespecification, angle θ is the upper right angle when the center is ontop and the outer edge is on the bottom-illustrated in FIGS. 1A and 2A.Advantageously, angle θ is 20 to 85° for inward biased grooves. Moreadvantageously, angle θ is 30 to 80° for inward biased grooves. Radialfeeder groove 20 intersects trapezoid groove regions 60, 62, 64, 66 and68 at an angle α₁. Radial feeder groove 22 intersects trapezoid grooveregions 60, 62, 64, 66 and 68 at an angle β₁. For inward biasedtrapezoid groove regions 60, 62, 64, 66 and 68, the angle of al is lessthan the angle of Pi.

Referring to FIG. 1B, polishing regions, 60, 62, 64, 66 and 68 are aseries of spaced non-isosceles trapezoid groove structures. Thetrapezoid groove structures have parallel base segments 160, 162, 164,166, 168 and 170 connecting two adjacent radial feeder grooves 20 and 22to form leg segments 20 a, 20 b, 20 c, 20 d and 20 e and 22 a, 22 b, 22c, 22 d and 22 e, respectively. The base segments 160, 162, 164, 166,168 and 170 intersect each of the leg segments (20 a, 20 b, 20 c, 20 dand 20 e) and (22 a, 22 b, 22 c, 22 d and 22 e) at different angles. Theseries of non-isosceles trapezoid groove structures extend from adjacentthe outer edge toward the center of the polishing pad. The perimeter ofthe series of trapezoid structures 60, 62, 64, 66 and 68 also is atrapezoid.

Rotation of the polishing pad moves polishing fluid through the basesegments 160, 162, 164, 166, 168 and 170 and the leg segments (20 a, 20b, 20 c, 20 d and 20 e) and (22 a, 22 b, 22 c, 22 d and 22 e) toward theouter edge of the polishing pad. In addition to the outward movement,the polishing fluid moves toward the wafer for clockwise rotation of thepolishing pad and also away from the wafer for counterclockwise rotationof the polishing pad. The motion of the polishing fluid toward the waferreduces residence time for slurry under the wafer and motion away fromthe wafer increases residence time for slurry under the wafer. Forexample, an inward bias can increase residence time for counterclockwiseplaten rotation. Advantageously, all the polishing regions have the samebias.

Referring to FIG. 1C during rotation, polishing fluid distributes ontothe rotating polishing pad and into the radial feeder groove 22 (22 a,22 b and 22 c) and the series of biased grooves 160, 161, 162 and 163.Centrifugal forces move polishing fluid toward the outer edge of thepolishing pad through the radial feeder groove 22 (22 a, 22 b and 22 c),and the series of bias grooves 160, 161, 162 and 163 in the direction ofthe arrows. In addition, polishing fluid moves outward by overflowingthe outer walls 160 a, 161 a, 162 a and 163 a to wet land areas 60 a, 61a, 62 a and 63 a, respectively. Then the polishing fluid flows intoinner walls 161 b and 160 b of subsequent bias grooves 160 and 162,respectively (other bias grooves not visible and inner walls not visiblefor the flow along land areas 60 a and 61 a). Flow arrows at inner wall160 b and outer wall 160 a illustrate flow of polishing fluid into andout of inward bias groove 160. Typically, bias grooves 160 and 162 donot align with bias grooves 161 and 163. This non-alignment of biasgrooves between adjacent polishing regions facilitates flow down radialfeeder groove 22 for improved slurry distribution. In alternativeembodiments, it is possible to align bias grooves of adjacent polishingregions.

Pressing and rotating the wafer against the rotating polishing pad formultiple rotations removes at least one component of the wafer with landareas 60 a, 61 a, 62 a and 63 a all wet by the overflowing polishingfluid.

Referring to FIGS. 1 to 1C, the polishing pad 10 preferably contains atleast 20 inward biased grooves, such as 160, 162, 164, 166, 168 and 170in each polishing region 40, 42, 44, 46, 48, 50, 52 and 54. These inwardbias grooves represent groove segments that connect between adjacentradial feeder grooves; and they combine to increase slurry residencetime under a wafer substrate with counterclockwise platen rotation. Morepreferably, the polishing pad 10 contains 20 to 1,000 inward biasedgrooves in each polishing region 40, 42, 44, 46, 48, 50, 52 and 54. Mostpreferably, the polishing pad 10 contains 20 to 500 inward biasedgrooves in each polishing region 40, 42, 44, 46, 48, 50, 52 and 54.

Typically, polishing pad 10 has at least 15 times of total inward biasedgrooves, such as 160, 162, 164, 166, 168 and 170 to total radial feedergrooves 20, 22, 24, 26, 28, 30, 32 and 34 (8). For example, there may be20 to 1,000 times as many total inward biased grooves to total radialfeeder grooves 20, 22, 24, 26, 28, 30, 32 and 34 (8) on the polishingpad 10. Preferably, there may be 20 to 500 times as many total inwardbiased grooves to total radial feeder grooves 20, 22, 24, 26, 28, 30, 32and 34 (8) on the polishing pad 10.

Referring to FIGS. 2 and 2A, the polishing pad 210 of the invention issuitable for polishing or planarizing at least one of semiconductor,optical and magnetic substrates. The polishing layer 212 has a polymericmatrix and a thickness 214. The polishing layer 212 includes a center216, an outer edge 218 and a radius (r) extending from the center 216 tothe outer edge 218. Advantageously the wafer remains positioned at alocation along the radius r from the center 216 of the polishing pad 210closer to the outer edge 218 of the polishing pad then the center 216 ofthe polishing pad 210 to increase removal rate of at least one componentof the wafer. Radial feeder grooves 220, 222, 224, 226, 228, 230, 232and 234 initiate from center 216 or from optional circular groove 236.Radial feeder grooves 220, 222, 224, 226, 228, 230, 232 and 234 separatethe polishing layer 212 into polishing regions 240, 242, 244, 246, 248,250, 252 and 254. In particular, two adjacent radial feeder grooves,such as 220 and 222, combine with perimeter arc 219 of outer edge 218 todefine polishing region 240. Polishing region 240, along with polishingregions 242, 244, 246, 248, 250, 252 and 254 have a shape of a circularsector with a small circular sector broken away at the center 216. Theradial feeder grooves 220, 222, 224, 226, 228, 230, 232 and 234advantageously extend at least from circular groove 236 adjacent thecenter 216 to or adjacent the outer edge 18.

Referring to FIGS. 2A and 2B, polishing region 240 includes a series ofstacked trapezoid groove regions 260, 262, 264, 266 and 268. Polishingregion 240 represents a circular sector of polishing pad 210 (FIG. 2)with the center region being groove-free. Parallel linear grooves orparallel base grooves 360, 362, 364, 366, 368 and 370 define the top andbottom of the trapezoid groove regions 260, 262, 264, 266 and 268.Radial feeder groove segments 220 a, 220 b, 220 c, 220 d and 220 e ofradial feeder groove 220 define the left side of trapezoid grooveregions 260, 262, 264, 266 and 268, respectively. Radial feeder groovesegments 222 a, 222 b, 222 c, 222 d and 222 e of radial feeder groove222 define the right side of trapezoid groove regions 260, 262, 264, 266and 268, respectively. Polishing regions 240, 242, 244, 246, 248, 250,252 and 254 (FIG. 2) all include a series of trapezoid groove regionsspaced with parallel base grooves. To accommodate the shape of acircular polishing pad 210 or a circular sector shape of polishingregions 240, 242, 244, 246, 248, 250, 252 and 254, trapezoid grooveregions are often cut to accommodate the outer edge 218 or circulargroove 236.

The trapezoid groove regions 260, 262, 264, 266 and 268 all representnon-isosceles trapezoid regions with the radial side segments being ofdifferent lengths. Because this grove pattern has an outward bias towardthe outer edge 218, radial feeder groove segments 220 a, 220 b, 220 c,220 d and 220 e are longer than radial 222 a, 222 b, 222 c, 222 d and222 e, respectively. In addition to each trapezoid groove regionrepresenting a non-isosceles trapezoid, the perimeter of stackedtrapezoid regions such as the perimeter of trapezoid regions 260 and262; and the perimeter of trapezoid regions 260, 262 and 264 also definea non-isosceles trapezoid. The trapezoid region 270 adjacent thecircular groove 236 has a portion broken away to accommodate thecircular groove 236. Similarly, trapezoid groove regions 280, 282, 284,286, 288, 290, 292, 294 and 296 adjacent outer edge 218 all haveportions broken away to accommodate the circular shape of the outer edge218 of the polishing pad 210. Rotating the polishing pad sends usedpolishing fluid through a portion of the series of biased groovesadjacent trapezoid groove regions 280, 282, 284, 286, 288, 290, 292, 294and 296 over the outer edge 218 of the polishing pad 210 to allow flowof new polishing fluid under the wafer.

Referring to FIG. 2A, the dashed line AA bisects polishing region 240 byconnecting center 216 to the midpoint of perimeter arc 219 of outer edge218. The base legs of spaced trapezoid groove regions 280, 282, 284,286, 288, 290 and 292 intersect line AA at an angle θ. For purposes ofthe specification, angle θ is the upper right angle when the center ison top and the outer edge is on the bottom-illustrated in FIGS. 1A and2A. Advantageously, angle θ is 95 to 160° for outward biased grooves.More advantageously, angle θ is 100 to 150° for outward biased grooves.Radial feeder groove 220 intersects trapezoid groove regions 260, 262,264, 266 and 268 at an angle α₂. Radial feeder groove 222 intersectstrapezoid groove regions 260, 262, 264, 266 and 268 at an angle β₂. Foroutward biased trapezoid groove regions 260, 262, 264, 266 and 268, theangle of α₂ is greater than the angle of β₂.

Referring to FIG. 2B, polishing regions, 260, 262, 264, 266 and 268 area series of spaced non-isosceles trapezoid groove structures. Thetrapezoid groove structures have parallel base segments 360, 362, 364,366, 368 and 370 connecting two adjacent radial feeder grooves 220 and222 to form leg segments 220 a, 220 b, 220 c, 220 d and 220 e and 222 a,222 b, 222 c, 222 d and 222 e, respectively. The base segments 360, 362,364, 366, 368 and 370 intersect each of the leg segments (220 a, 220 b,220 c, 220 d and 220 e) and (222 a, 222 b, 222 c, 222 d and 222 e) atdifferent angles. The series of non-isosceles trapezoid groovestructures extend from adjacent the outer edge toward the center of thepolishing pad. The perimeter of the series of trapezoid structures 260,262, 264, 266 and 268 also is a trapezoid.

Rotation of the polishing pad moves polishing fluid through the basesegments 360, 362, 364, 366, 368 and 370 and the leg segments (220 a,220 b, 220 c, 220 d and 220 e) and (222 a, 222 b, 222 c, 222 d and 222e) toward the outer edge of the polishing pad. In addition to theoutward movement, the polishing fluid moves toward the wafer forclockwise rotation of the polishing pad and also away from the wafer forcounterclockwise rotation of the polishing pad. The motion of thepolishing fluid toward the wafer reduces residence time for slurry underthe wafer and motion away from the wafer increases residence time forslurry under the wafer. For example, an outward bias can decreaseresidence time for counterclockwise platen rotation. Advantageously, allthe polishing regions have the same bias.

Referring to FIG. 2C, during rotation, polishing fluid distributes ontothe rotating polishing pad and into the radial feeder groove 222 (222 a,222 b and 222 c) and the series of biased grooves 360, 361, 362 and 163.Centrifugal forces move polishing fluid toward the outer edge of thepolishing pad through the radial feeder groove 222 (222 a, 222 b and 222c), and the series of bias grooves 360, 361, 362 and 363 in thedirection of the arrows. In addition, polishing fluid moves outward byoverflowing the outer walls 360 a, 361 a, 362 a and 363 a to wet landareas 260 a, 261 a, 262 a and 263 a, respectively. Then the polishingfluid flows into inner walls 361 b and 360 b of subsequent bias grooves360 and 362, respectively (other bias grooves not visible and innerwalls not visible for the flow along land areas 60 a and 61 a). Flowarrows at inner wall 360 b and outer wall 360 a illustrate flow ofpolishing fluid into and out of outward bias groove 360. Typically, biasgrooves 360 and 362 do not align with bias grooves 361 and 363. Thisnon-alignment of bias grooves between adjacent polishing regionsfacilitates flow down radial feeder groove 222 for improved slurrydistribution. In alternative embodiments, it is possible to align biasgrooves of adjacent polishing regions. Pressing and rotating the waferagainst the rotating polishing pad for multiple rotations removes atleast one component of the wafer with land areas 260 a, 261 a, 262 a and263 a all wet by the overflowing polishing fluid.

Referring to FIGS. 2 to 2C, the polishing pad 210 preferably contains atleast 20 outward biased grooves such as 260, 262, 264, 266, 268 and 270in each polishing region 240, 242, 244, 246, 248, 250, 252 and 254.These outward bias grooves represent groove segments that connectbetween adjacent radial feeder grooves; and they combine to decreaseslurry residence time under a wafer substrate with counterclockwiseplaten rotation. More preferably, the polishing pad 210 contains 20 to1,000 outward biased grooves in each polishing region 240, 242, 244,246, 248, 250, 252 and 254. Most preferably, the polishing pad 210contains 20 to 500 outward biased grooves in each polishing region 240,242, 244, 246, 248, 250, 252 and 254.

Typically, polishing pad 210 has at least 15 times of total outwardbiased grooves, such as 360, 362, 364, 166, 368 and 370 to total radialfeeder grooves 220, 222, 224, 226, 228, 230, 232 and 234 (8). Forexample, there may be 20 to 1,000 times as many total outward biasedgrooves to total radial feeder grooves 220, 222, 224, 226, 228, 230, 232and 234 (8) on the polishing pad 210. Preferably, there may be 20 to 500times as many total outward biased grooves to total radial feedergrooves 220, 222, 224, 226, 228, 230, 232 and 234 (8) on the polishingpad 210.

Referring to FIGS. 3 and 3A, slurry flow vectors illustrate howcentrifugal motion of the polishing pad results in outward motion of thepolishing fluid through the bias grooves 3-3 and 3 a-3 a. Arrowsillustrate counter clockwise platen rotation direction with DPrepresenting a typical slurry drop point. The slurry vector intersectsat point W that represents a slurry flow point under a wafer. In thecase of an inward bias groove (FIG. 3), V_(ib) represents the outwardvelocity of polishing fluid through an inward bias groove 3-3 and V_(N)represents the slurry flow normal to the inward bias groove 3-3. Theresulting slurry flow V_(T) or velocity total becomes slower withrespect to the wafer to increase polishing fluid residence time underthe wafer. In the case of an outward bias groove (FIG. 3A), V_(ob)represents the outward velocity of polishing fluid through an outwardbias groove 3 a-3 a and V_(N) represents the slurry flow normal to theinward bias groove 3 a-3 a. The resulting slurry flow V_(T) or velocitytotal becomes faster with respect to the wafer to decrease polishingfluid residence time under the wafer. With this groove configuration,platen velocity and bias angle combine to control polishing fluidresidence time.

Referring to FIG. 4, inward bias polishing pad 400 has three polishingregions 402, 404 and 406. Radial feeder grooves 408, 410 and 412separate the polishing pad 400 into the polishing regions 402, 404 and406 of equal size separated by 120 degrees. In an alternative embodimentnot shown, it is possible to separate the polishing regions into twosizes, such as 100 degrees, 100 degrees and 160 degrees. In a furtheralternative embodiment, it is possible to separate the polishing regionsinto three different sizes, such as 100 degrees, 120 degrees and 140degrees. As polishing pad 400 rotates, the long biased grooves sweep thewafer to improve removal rate. With this embodiment, it is advantageousfor the radial feeder grooves 408, 410 and 412 to have a larger crosssection than the biased grooves to improve distribution of the polishingfluid.

Referring to FIG. 4A, outward bias polishing pad 450 has three polishingregions 452, 454 and 456. Radial feeder grooves 458, 460 and 462separate the polishing pad 450 into the polishing regions 452, 454 and456 of equal size separated by 120 degrees. In an alternative embodimentnot shown, it is possible to separate the polishing regions into twosizes, such as 100 degrees, 100 degrees and 160 degrees. In a furtheralternative embodiment, it is possible to separate the polishing regionsinto three different sizes, such as 100 degrees, 120 degrees and 140degrees. As polishing pad 450 rotates, the long biased grooves sweep thewafer to improve removal rate. With this embodiment, it is advantageousfor the radial feeder grooves 458, 460 and 462 to have a larger crosssection than the biased grooves to improve distribution of the polishingfluid.

Referring to FIG. 5, inward bias polishing pad 500 has four polishingregions 502, 504, 506 and 508. Radial feeder grooves 510, 512, 514 and516 separate the polishing pad 500 into the polishing regions 502, 504,506 and 508 of equal size separated by 90 degrees. In an alternativeembodiment not shown, it is possible to separate the polishing regionsinto two sizes, such as 80 degrees, 100 degrees, 80 degrees and 100degrees. In a further alternative embodiment, it is possible to separatethe polishing regions into four different sizes, such as 70 degrees, 110degrees, 80 degrees and 100 degrees. Furthermore, it is possible tochange the order of the polishing regions. As polishing pad 500 rotates,the biased grooves sweep the wafer to improve removal rate. With thisembodiment, it is advantageous for the radial feeder grooves 510, 512,514 and 516 to have a larger cross section than the biased grooves toimprove distribution of the polishing fluid.

Referring to FIG. 5A, outward bias polishing pad 550 has four polishingregions 552, 554, 556 and 558. Radial feeder grooves 560, 562, 564 and566 separate the polishing pad 550 into the polishing regions 552, 554,556 and 558 of equal size separated by 90 degrees. In an alternativeembodiment not shown, it is possible to separate the polishing regionsinto two sizes, such as 80 degrees, 100 degrees, 80 degrees and 100degrees. In a further alternative embodiment, it is possible to separatethe polishing regions into four different sizes, such as 70 degrees, 80degrees, 100 degrees and 110 degrees. Furthermore, it is possible tochange the order of the polishing regions. As polishing pad 550 rotates,the biased grooves sweep the wafer to improve removal rate. With thisembodiment, it is advantageous for the radial feeder grooves 560, 562,564 and 566 to have a larger cross section than the biased grooves toimprove distribution of the polishing fluid.

Referring to FIG. 6, inward bias polishing pad 600 has five polishingregions 602, 604, 606, 608 and 610. Radial feeder grooves 612, 614, 616,618 and 620 separate the polishing pad 600 into the polishing regions602, 604, 606, 608 and 610 of equal size separated by 72 degrees. In analternative embodiment not shown, it is possible to separate thepolishing regions into two sizes, such as 60 degrees, 90 degrees, 60degrees, 90 degrees and 60 degrees. In a further alternative embodiment,it is possible to separate the polishing regions into five differentsizes, such as 52 degrees, 62 degrees, 72 degrees, 82 degrees and 92degrees. Furthermore, it is possible to change the order of thepolishing regions. As polishing pad 600 rotates, the biased groovessweep the wafer to improve removal rate and additional radial feedergrooves facilitate polishing fluid distribution. With this embodiment,it is advantageous for the radial feeder grooves 612, 614, 616, 618 and620 to have a larger cross section than the biased grooves to improvedistribution of the polishing fluid.

Referring to FIG. 6A, outward bias polishing pad 650 has five polishingregions 652, 654, 656, 658 and 660. Radial feeder grooves 662, 664, 666,668 and 670 separate the polishing pad 650 into the polishing regions652, 654, 656, 658 and 660 of equal size separated by 72 degrees. In analternative embodiment not shown, it is possible to separate thepolishing regions into two sizes, such as 60 degrees, 90 degrees, 60degrees, 90 degrees and 60 degrees. In a further alternative embodiment,it is possible to separate the polishing regions into five differentsizes, such as 52 degrees, 62 degrees, 72 degrees, 82 degrees and 92degrees. Furthermore, it is possible to change the order of thepolishing regions. As polishing pad 650 rotates, the biased groovessweep the wafer to improve removal rate and additional radial feedergrooves facilitate polishing fluid distribution. With this embodiment,it is advantageous for the radial feeder grooves 662, 664, 666, 668 and670 to have a larger cross section than the biased grooves to improvedistribution of the polishing fluid.

Referring to FIG. 7, inward bias polishing pad 700 has six polishingregions 702, 704, 706, 708, 710 and 712. Radial feeder grooves 714, 716,718, 720, 722 and 724 separate the polishing pad 700 into the polishingregions 702, 704, 706, 708, 710 and 712 of equal size separated by 60degrees. In an alternative embodiment not shown, it is possible toseparate the polishing regions into two sizes, such as 50 degrees, 70degrees, 50 degrees, 70 degrees, 50 degrees and 70 degrees. In a furtheralternative embodiment, it is possible to separate the polishing regionsinto six different sizes, such as 30 degrees, 40 degrees, 50 degrees, 70degrees, 80 degrees and 90 degrees. Furthermore, it is possible tochange the order of the polishing regions. As polishing pad 700 rotates,the biased grooves sweep the wafer to improve removal rate andadditional radial feeder grooves facilitate polishing fluiddistribution. With this embodiment, it is advantageous for the radialfeeder grooves 714, 716, 718, 720, 722 and 724 to have a larger crosssection than the biased grooves to improve distribution of the polishingfluid.

Referring to FIG. 7A, outward bias polishing pad 750 has six polishingregions 752, 754, 756, 758, 760 and 762. Radial feeder grooves 764, 766,768, 770, 772 and 774 separate the polishing pad 750 into the polishingregions 752, 754, 756, 758, 760 and 762 of equal size separated by 60degrees. In an alternative embodiment not shown, it is possible toseparate the polishing regions into two sizes, such as 50 degrees, 70degrees, 50 degrees, 70 degrees, 50 degrees and 70 degrees. In a furtheralternative embodiment, it is possible to separate the polishing regionsinto six different sizes, such as 30 degrees, 40 degrees, 50 degrees, 70degrees, 80 degrees and 90 degrees. Furthermore, it is possible tochange the order of the polishing regions. As polishing pad 750 rotates,the biased grooves sweep the wafer to improve removal rate andadditional radial feeder grooves facilitate polishing fluiddistribution. With this embodiment, it is advantageous for the radialfeeder grooves 764, 766, 768, 770, 772 and 774 to have a larger crosssection than the biased grooves to improve distribution of the polishingfluid.

Referring to FIG. 1, inward bias polishing pad 10 has eight polishingregions 40, 42, 44, 46, 48, 50, 52 and 54. Radial feeder grooves 20, 22,24, 26, 28, 30, 32 and 34 separate the polishing pad 10 into thepolishing regions 40, 42, 44, 46, 48, 50, 52 and 54 of equal sizeseparated by 45 degrees. In an alternative embodiment not shown, it ispossible to separate the polishing regions into two sizes, such as 35degrees, 55 degrees, 35 degrees, 55 degrees, 35 degrees, 55 degrees, 35degrees and 55 degrees. In a further alternative embodiment, it ispossible to separate the polishing regions into eight different sizes,such as 25 degrees, 30 degrees, 35 degrees, 40 degrees, 50 degrees, 55degrees, 60 degrees and 65 degrees. Furthermore, it is possible tochange the order of the polishing regions. As polishing pad 10 rotates,the biased grooves sweep the wafer to improve removal rate andadditional radial feeder grooves facilitate polishing fluiddistribution. With this embodiment, it is advantageous for the radialfeeder grooves 20, 22, 24, 26, 28, 30, 32 and 34 to have a larger crosssection than the biased grooves to improve distribution of the polishingfluid. Rotating the polishing pad alternates the wafer between beingover one radial feeder groove and being over two radial feeder grooves.

Referring to FIG. 2, outward bias polishing pad 210 has eight polishingregions 240, 242, 244, 246, 248, 250, 252 and 254. Radial feeder grooves220, 222, 224, 226, 228, 230, 232 and 234 separate the polishing pad 210into the polishing regions 240, 242, 244, 246, 248, 250, 252 and 254 ofequal size separated by 45 degrees. In an alternative embodiment notshown, it is possible to separate the polishing regions into two sizes,such as 35 degrees, 55 degrees, 35 degrees, 55 degrees, 35 degrees, 55degrees, 35 degrees and 55 degrees. In a further alternative embodiment,it is possible to separate the polishing regions into eight differentsizes, such as 25 degrees, 30 degrees, 35 degrees, 40 degrees, 50degrees, 55 degrees, 60 degrees and 65 degrees. Furthermore, it ispossible to change the order of the polishing regions. As polishing pad210 rotates, the biased grooves sweep the wafer to improve removal rateand additional radial feeder grooves facilitate polishing fluiddistribution. With this embodiment, it is advantageous for the radialfeeder grooves 220, 222, 224, 226, 228, 230, 232 and 234 to have alarger cross section than the biased grooves to improve distribution ofthe polishing fluid.

Referring to FIGS. 8 and 8A, curving the biased grooves 810 and 860 ofpolishing pads 800 and 850, respectively can facilitate uniform flow ofpolishing fluid over groove land areas. Polishing pads 800 and 850 haveoutward bias grooves 810 and 860. As the polishing pads 800 and 850rotate, polishing fluid flows out the grooves 810 and 860 toward theouter edge 812 and 862. In grooves 810 and 860, the outward slope of thegrooves diminish as it travels outward, this slows outward velocity andfacilitates polishing fluid wetting the land areas toward the end of thegrooves 810 and 860 during both clockwise and counterclockwise rotation.

For these configurations and for purposes of the specification, the biasangle θ equals the average angle of the curved biased grooves inrelation to the bisect line represented by a dashed line. One method formeasuring bias angle as seen in FIG. 8 is to draw an imaginary line 8-8that connects adjacent radial feeder grooves 820 and 830 along a singlecurved biased groove, then measure the angle of intersection (θ) or biasangle with dashed bisect line B₈. Similarly, for FIG. 8A, imaginary line8 a-8 a connects adjacent radial feeder grooves 870 and 872 along asingle curved bias groove, then measuring the angle of intersection withdashed bisect line B_(8a) equals the bias angle, θ. It is important thatat least a majority of each curved bias segment have either an inward oroutward angle.

Advantageously, at a majority of the bias grooves have the same bias.This is because having an inward biased groove portion with an outwardbiased groove portion will tend to cancel each other out with respect toremoval rate. Advantageously, all the bias segments have either aninward or outward bias.

Referring to FIG. 9, polishing pad 900 has curved radial feeder grooves910, 912, 914 and 916. The feeder grooves 910, 912, 914 and 916 curvecounter counterclockwise to improve fluid flow for clockwise rotation ofpolishing pad 900. This shape accelerates outward flow of the polishingfluid to improve polishing fluid distribution to outer bias grooves 920during clockwise rotation and decelerates outward flow to decreasepolishing fluid distribution to outer bias grooves 920 duringcounterclockwise rotation. Alternatively, the radial feeder groovescould curve in a clockwise direction (not shown) for the oppositeimpact. This shape decelerates outward flow of the polishing fluid toimprove polishing fluid distribution to outer bias grooves 920 duringcounterclockwise rotation and accelerates outward flow to decreasepolishing fluid distribution to outer bias grooves 920 during clockwiserotation.

Measuring bias angle for FIG. 9 having curved radial feeder grooves 914and 916, requires drawing of dashed radial lines Ra and Rb withimaginary bisect line B₉ that bisects dashed radial lines Ra and Rb.This illustrates the bias angle θ for outward bias groove 930 thatintersects bisect line B₉. Chords Ra₁ and Rb₁ have equal length and areparallel radial lines Ra and Rb, respectively. A dashed line Ra₁-Rb₁connects ends of chords Ra₁ and Rb₁ and intersects with bisect line B₉at bias groove 930. The bias angle for groove 930 is the angle betweenbisect line B₉ and groove 930 or 0. This embodiment has a constant θalong each bias groove and throughout the entire polishing region.

Referring to FIG. 10, polishing pad 1000 includes curved radial feedergrooves 1010, 1012, 1014 and 1016 combined with outward biased curvedgrooves 1020. In particular, this groove pattern includes curved radialfeeder grooves 1010, 1012, 1014 and 1016 to fine tune or adjustpolishing fluid near the outer edge 1022 of the polishing pad 1000.Furthermore, outward biased curved grooves 1020 serve to balancepolishing fluid flow onto land area within polishing regions 1030, 1032and 1034.

Measuring bias angle for FIG. 10 having curved radial feeder grooves1014 and 1016, requires drawing of dashed radial lines Ra and Rb withimaginary bisect line B₁₀ that bisects dashed radial lines Ra and Rb.This illustrates the bias angle θ for outward bias groove 1040 thatintersects bisect line B₁₀. Chords Ra₁ and Rb₁ have equal length and areparallel radial lines Ra and Rb, respectively. A dashed line Ra₁-Rb₁connects ends of chords Ra₁ and Rb₁ and intersects with bisect line B₉at bias groove 1040. The bias angle for groove 1040 is the angle betweenbisect line B₁₀ and a line that connects the ends of groove 1040 or θ.This embodiment has a θ that increases with each bias groove spacedfarther away from the polishing pad 1000.

Referring to FIGS. 11, 11A and 11B, polishing pad 1100 include steppedradial feeder grooves 1110, 1112, 1114 and 1116. This shape deceleratesoutward flow of the polishing fluid to improve polishing fluiddistribution to outer bias grooves 1120, 1122 and 1124 during clockwiserotation and accelerates outward flow to decrease polishing fluiddistribution to outer bias grooves 1120, 1122 and 1124 duringcounterclockwise rotation. Alternatively, the radial feeder groovescould curve in a clockwise direction (not shown) for the oppositeimpact. This shape decelerates outward flow of the polishing fluid toimprove polishing fluid distribution to outer bias grooves 1120, 1122and 1124 during counterclockwise rotation and decelerates outward flowto decrease polishing fluid distribution to outer bias grooves 1120,1122 and 1124 during clockwise rotation. Outward curved radial biasgrooves 1120, inward radial bias grooves 1122 and inward parallel radialbias grooves 1124 all serve to adjust, residence time of the polishingfluid under the wafer and fine tune polishing profile. In addition, itis possible to adjust the edge profile by adjusting platen or waferrotation speed. For example, increasing platen or wafer speed can changecenter fast polishing into a flat profile. This effect becomes much morepronounced when the wafer does not oscillate between the center and theedge of the polishing pad.

Referring to FIG. 11, imaginary line 11-11 connects a single biasgroove. The angle between imaginary line 11-11 and radial feeder grooves1114 and 1116 at the bisect line B₁₁₋₁ represents θ₁ or the bias anglefor the first portion of the polishing region. This portion of thepolishing region has a bias angle that decreases for each biased groovedspaced from the center of the polishing pad.

The second region requires the drawing of radial lines Ra and Rb andB₁₁₋₂ that bisects the radial lines Ra and Rb. Radial chords Ra₁ and Rb₁have equal length and are parallel radial lines Ra and Rb, respectivelyDashed line B₁₁₋₂ represents the bisect of these radial chords.Imaginary line Ra₁-Rb₁ connects Ra₁ and Rb₁ and passes through theintersection of bias groove 1130 and bisect line B₁₁₋₂. The intersectionof a line that connects the ends of bias groove 1130 with bisect lineB₁₁₋₂ represents the bias angle or θ₂. This portion of the polishingregion also has a bias angle that decreases for each biased groovedspaced from the center of the polishing pad.

Referring to FIGS. 12 and 12A, polishing pad 1200 may contain a seriesof stepped bias grooves 1202 and 1204, respectively, connecting radialfeeder grooves 1210, 1220, 1230 and 1240. The stepped bias grooves 1202and 1204 have segments 1202 a and 1202 b and 1204 having segments 1204 aand 1204 b, each separated by a dashed line for purposes ofillustration. FIG. 12 has inward biased stepped grooves 1202, dividedinto equal parts of groove segment 1202 a and 1202 b. In thisconfiguration, slurry first travels with a shallow bias through groovesegment 1202 a then at an increased rate through groove segment 1202 bhaving a steeper slope. FIG. 12A has biased stepped grooves 1204,divided into unequal parts of groove segment 1204 a and 1204 b. In thisconfiguration, slurry first travels with a steep bias through groovesegment 1204 a then at a decreased rate through groove segment 1204 bhaving a shallower slope. It is possible to use the segment spacing andslope to adjust wafer profile and edge profile.

Referring to FIG. 13, polishing pad 1300 includes outward biased steppedgrooves 1302 interconnecting adjacent stepped radial feeder grooves1310, 1320 1330 and 1340. The stepped bias grooves 1302 have segments1302 a and 1202 b, each separated by a dashed line for purposes ofillustration. The location of the step and slope at the step for boththe radial feeder groove and the stepped bias grooves impacts polishingremoval rate, wafer profile and edge profile.

Referring to FIGS. 14, 14A, 14B and 14C, polishing pads can include twoor more groove regions with different pitches or different crosssectional areas. FIGS. 14, 14A, 14C all include inward spacing regionhaving three regions as follows: (a) grooves at a first normal pitch,(b) grooves at an increased pitch and (c) grooves with a pitch equal toregion (a). This groove spacing is effective for eliminating center fastwafer profiles. Fine tuning of wafer profile is possible by adjustingthe width of each groove region and the density of grooves within eachgroove region. Adjusting groove spacing has particular impact uponimproving wafer edge profile. As seen in FIG. 14, the biased grooves maybe parallel linear grooves, parallel curved grooves or stepped grooves.These grooves may have equal or unequal spacing.

Referring to FIGS. 15, 15A, 15B and 15C, polishing pads can include twoor more groove regions with different pitches or different crosssectional areas. FIGS. 15, 15A, 15B and 15C all include inward spacingregion having three regions as follows: (A) grooves at a first increasedpitch, (B) grooves at a normal pitch and (C) grooves with a pitch equalto region (A). This groove spacing is effective for eliminating centerslow wafer profiles. Fine tuning of wafer profile is possible byadjusting the width of each groove region and the density of grooveswithin each groove region. Adjusting groove spacing has particularimpact upon improving wafer edge profile. As seen in FIG. 15, the biasedgrooves may be parallel linear grooves, parallel curved grooves orstepped grooves. These grooves may have equal or unequal spacing.

We claim:
 1. A method for polishing or planarizing a wafer of at leastone of semiconductor, optical and magnetic substrates, the methodcomprising the following: rotating a polishing pad, the polishing padhaving a polishing layer having a polymeric matrix and a thickness, thepolishing layer including a center, an outer edge and a radius extendingfrom the center to the outer edge of the polishing pad; radial feedergrooves in the polishing layer separating the polishing layer intopolishing regions, the radial feeder grooves extending at least from alocation adjacent the center to a location adjacent the outer edge; andeach polishing region including a series of biased grooves connecting apair of adjacent radial feeder grooves, a majority of the biased grooveshaving either an inward bias toward the center or an outward bias towardthe outer edge of the polishing pad, both the inward and outward biasedgrooves moving polishing fluid toward the outer edge of the polishingpad and either toward the wafer or away from the wafer depending uponinward bias or outward bias and the direction of rotation of thepolishing pad; distributing polishing fluid onto the rotating polishingpad and into the radial feeder grooves and the series of biased grooves;and pressing and rotating the wafer against the rotating polishing padfor multiple rotations of the polishing pad at a fixed distance from thecenter of the polishing pad, the wafer being closer to the outer edge ofthe polishing pad then the center of the polishing pad to increaseremoval rate of at least one component of the wafer.
 2. The method ofclaim 1 wherein rotating the polishing pad sends used polishing fluidthrough a portion of the series of biased grooves over the outer edge ofthe polishing pad to allow flow of new polishing fluid under the wafer.3. The method of claim 1 wherein the series of biased grooves representparallel grooves that increase residence time of the polishing fluidunder the wafer.
 4. The method of claim 1 wherein the series of biasedgrooves represent parallel grooves that decrease residence time of thepolishing fluid under the wafer.
 5. The method of claim 1 whereinrotating the polishing pad alternates the wafer between being over oneradial feeder groove and being over two radial feeder grooves.
 6. Amethod for polishing or planarizing a wafer of at least one ofsemiconductor, optical and magnetic substrates, the method comprisingthe following: rotating a polishing pad, the polishing pad having apolishing layer having a polymeric matrix and a thickness, the polishinglayer including a center, an outer edge and a radius extending from thecenter to the outer edge of the polishing pad; radial feeder grooves inthe polishing layer separating the polishing layer into polishingregions, the polishing regions being circular sectors defined by twoadjacent radial feeder grooves, a bisect line bisecting the polishingregions, the radial feeder grooves extending at least from a locationadjacent the center to a location adjacent the outer edge; and eachpolishing region including a series of biased grooves connecting a pairof adjacent radial feeder grooves, a majority of the biased grooveshaving either an inward bias toward the center of the polishing pad atan angle of 20° to 85° from the bisect line or an outward bias towardthe outer edge of the polishing pad at an angle of 95° to 160° from thebisect line, both the inward and outward biased grooves moving polishingfluid toward the outer edge of the polishing pad and either toward thewafer or away from the wafer depending upon inward bias or outward biasand the direction of rotation of the polishing pad; distributingpolishing fluid onto the rotating polishing pad and into the radialfeeder grooves and the series of biased grooves; and pressing androtating the wafer against the rotating polishing pad for multiplerotations of the polishing pad at a fixed distance from the center ofthe polishing pad, the wafer being closer to the outer edge of thepolishing pad then the center of the polishing pad to increase removalrate of at least one component of the wafer.
 7. The method of claim 6wherein rotating the polishing pad sends used polishing fluid through aportion of the series of biased grooves over the outer edge of thepolishing pad to allow flow of new polishing fluid under the wafer. 8.The method of claim 6 wherein the series of biased grooves representparallel grooves that increase residence time of the polishing fluidunder the wafer.
 9. The method of claim 6 wherein the series of biasedgrooves represent parallel grooves that decrease residence time of thepolishing fluid under the wafer.
 10. The method of claim 6 whereinrotating the polishing pad alternates the wafer between being over oneradial feeder groove and being over two radial feeder grooves.